You can also try our MDSPICE simulator which basically accept the SPICE
netlist (limited to R, L, C, K) and s-parameter files compatible with the HP
measurement results in files. We also offer accurate and efficient full wave
simulators. Thanks!

Nilesh
Please contact Art Frasier at Intel, Santa Clara. He has HP MDS/ADS
which
can used measured S-parameters together with other frequency dependent
elements
and transfer them back into the time domain.

Ron Miller

Steve Corey wrote:

Nilesh -- SPICE-like simulators doing time-domain analyses solve
their differential equations in the time domain, based on the charge/flux
stored in
capacitors/inductors and the derivatives of the voltage/current
variables at each node/branch. A time-domain simulator has no concept of
frequency.
It is quite possible to get frequency dependence included in a model
for a time-domain simulator, since L's and C's are frequency-dependent
impedances/admittances and can be shown, when used in conjunction
with R's (and inductance coupling coeffficients) to accurately represent any
well-behaved
function if used in the correct topology and with the correct
values. However, for certain structures (e.g., long cables used at high
frequencies) a large
number of lumped elements is required to represent the delay.

A full wave solver is one of many approaches to getting a frequency
dependent model. Other approaches, such as 2-D solvers, may be quite
sufficient
without going to such great lengths -- you have to evaluate what
frequency-dependent effects you are trying to model. /* begin brazen
advertising */ We
offer a tool which extracts models from measured data and handles
some effects, such as non-uniform impedance and next-door coupling, quite
well. /* end
brazen advertising */ General full-wave modeling from measurement is
on the horizon, and is a current research topic in academia, but we do not
offer it at
this time.

> Hi:
> I have a question:
> It's all well and fine to build frequency dependent MODELS,
> but what about the simulator(ex Hspice) itself?
> For example, if I feed the output of a simple inverter to an
> L,C, R network, (and I'm doing a simple time domain transient
analysis)
>
> INVERTER------LRC NETWORK----OUTPUT
>
> does the simulator decompose the output waveform of the inverter
> into it's frequency components before feeding it into the LC
network?(i
> don't think so)
> For example, if the output of my buffer looks like a repeating
square pulse
> running at 400Mhz 50% duty cycle with a finite rise time, does the
LRC
> network "see"
> the input wave as
> Asin(w1t)+Bsin(w2t)+..... etc
> where w1=400Mhz and w2,w3 etc are the harmonics?Or does one have
to
> explicitly
> take the output of the waveform, decompose it and then feed it
artificially
> to the LRC network?
>
> or does the LRC network "see" as it's input,a bunch of dc points
for
> which the simulator solves the nodal matrix using difference or
differential
> equations? i.e. does the LRC network "see" only 1 frequency coming
in which
> is the fundamental?
>
> How does this work?How is the frequency content of the output
waveform of
> the buffer conveyed to the LCR network?
> I was planning to investigate this but I thought some of
> you experts out there might have the answer at the top of your
head...
>
> Also, tools like Ansoft Q3d extract models only at 1 frequency(I
think), so
> unless you use HFSS, how do you get a true frequency dependent
model?
> I've generated R,L versus frequency and other parameter versus
frequency
> curves, but this is with 2 d models using TEM assumptions.what
about 3-d
> models?
> is ther ANY way at all except for using a full wave solver like
HFSS to
> generate true frequency
> dependent models and simulate in the time domain?
>
> Thanks for your ideas in advance.
> Nilesh
>
>
> Nilesh N Shah,
> Package Electrical Design Engineer,
> PCG, Folsom, CA.
> Intel Corporation.
> tel:916-356 1129.
>
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